Medical robotic systems such as those used in performing minimally invasive surgical procedures offer many benefits over traditional open surgery techniques, including less pain, shorter hospital stays, quicker return to normal activities, minimal scarring, reduced recovery time, and less injury to tissue. Consequently, demand for minimally invasive surgery using such medical robotic systems is strong and growing.
Examples of medical robotic systems include the da Vinci® Surgical System and the da Vinci® S™ Surgical System from Intuitive Surgical, Inc., of Sunnyvale, Calif. Each of these systems includes a surgeon's console, a patient-side cart, a high performance three-dimensional (“3-D”) vision system, and Intuitive Surgical's proprietary EndoWrist® articulating instruments, which are modeled after the human wrist so that when added to the motions of manipulators holding the surgical instruments, they allow at least six degrees of freedom of motion, which is comparable to or even greater than the natural motions of open surgery.
The da Vinci® surgeon's console has a high-resolution stereoscopic video display with two progressive scan cathode ray tubes (“CRTs”). The system offers higher fidelity than polarization, shutter eyeglass, or other techniques. Each eye views a separate CRT presenting the left or right eye perspective, through an objective lens and a series of mirrors. The surgeon sits comfortably and looks into this display throughout surgery, making it an ideal place for the surgeon to display and manipulate 3-D intraoperative imagery.
The patient-side cart typically includes three or more robotic arm assemblies with corresponding slave manipulators for holding and manipulating medical devices such as surgical instruments and image capturing devices for performing and/or viewing a medical procedure at a surgical site within a patient. To manipulate these medical devices, the surgeon's console also includes input devices which may be selectively associated with the medical devices and their respective slave manipulators. Since the movements of the input devices and their associated medical devices are scaled, this allows the surgeon to perform intricate medical procedures with greater ease than conventional open surgery. Further, it may even allow the surgeon to perform medical procedures that are not even feasible using conventional open surgery techniques.
During or before performing a medical procedure at a work site in a patient, it may be necessary or desirable to position and/or orient an image capturing device, such as a stereoscopic endoscope or ultrasound probe, so as to provide the surgeon a better view of the procedure on the display screen. Because the image capturing device generally has fewer degrees-of-freedom than a master control used for such positioning and orienting, unused degrees-of-freedom of the master control are available for control and other purposes. As an example, U.S. Pat. No. 6,799,065 entitled “Image Shifting Apparatus and Method for a Telerobotic System,” which is incorporated herein by this reference, describes the possible use of an unused degree-of-freedom of a master control for focus or zoom control of a camera.
A number of practical problems may need to be overcome, however, in order to employ an unused degree-of-freedom of a master control for adjusting an attribute of an image capturing device where the master control is also associated at the time with the image capturing device for positioning and/or orienting the image capturing device. For example, one problem with such employment is that the controlling of the positioning and/or orienting of the image capturing device may result in a set-point of the unused degree-of-freedom changing. Another problem is possible inadvertent movement of the unused degree of freedom by the human operator using the master control.